Apparatus for dispensing particulate material and components therefor

ABSTRACT

A particular dispensing apparatus ( 10 ) for dispensing with particular refractory material into a gap between a furnace wall and a form includes a platform ( 12 ) removably engaging the upper end of an expendable metal form. A carriage ( 14 ) is pivotally coupled to the platform and is rotatable about a pivot point located generally at the center of the platform. A hopper ( 30 ) is coupled to the carriage. The hopper receives particulate refractory material via an inlet and dispenses the particulate refractory material through an outlet ( 36 ). A feeder ( 34 ) is coupled to the outlet of the hopper to move the particulate refractory material from the outlet to a dispenser ( 44 ). The dispenser is coupled to the carriage at a distal end of the feeder and is suspended above the lining gap to deliver particulate refractory material into the lining gap. An air extractor device ( 170 ) is coupled to the carriage for removing air from particulate refractory material in the lining gap and for re-compacting the particulate refractory material.

TECHNICAL FIELD

The present invention relates to an apparatus for use in producing arefractory lining within a foundry furnace, in particular, to anapparatus for dispensing particulate refractory material into an annularspace defined between an inner furnace surface and an expendable metalform within the furnace, in preparation for sintering into a continuouslining.

BACKGROUND ART

A common foundry induction furnace typically comprises a cylindricalfurnace wall including an induction heating coil, and a continuouslining formed of sintered silica or other refractory material defining achamber for containing molten metal, such as iron melt. From time totime, the lining becomes eroded and requires replacement. Followingremoval of the worn lining an expendable steel cylindrical form isconcentrically installed within the furnace. The outer surface of theform is spaced apart from the inner surface of the furnace so as todefine an annular space therebetween. Refractory particulate material isthen manually poured into the annular space. Once the annular space hasbeen filled, the refractory material is sintered first by gas heatersfired into the furnace, and thereafter by an initial charge of molteniron melted within the furnace. The initial charge also melts theexpendable form to reveal the sintered lining.

Manual pouring of the refractory material into the annular space isstrenuous, labor intensive work. Workers are required to wear protectiveclothing and use respirators to guard against airborne particulate dustthat may pose health risks. Foundries are under increased pressure tooperate within environmental guidelines, and therefore, manual pouringof refractory material has become increasingly undesirable. In addition,during manual pouring of the refractory material air tends to beentrapped in the particulate material resulting in voids in the liningthat physically weaken the lining or create pockets of over heatedmetal. Human variability, such as inexperience and fatigue, results ininconsistencies in the lining, which lead to unpredictable refractorylife and production schedules from one lining to the next.

To deal with the problems associated with manual pouring of refractorymaterial, an automated particle dispensing apparatus has been consideredand is disclosed in U.S. Pat. No. 5,058,776. Although this apparatusproduces more consistent linings than the manual method, it has beenfound that when pouring refractory material having fine grain sizes ofparticulate material the apparatus does not always deliver a smooth flowof refractory material into the annular space. This can result in anuneven distribution of particulate material, which may produce asubstandard lining.

It is therefore an object of the present invention to provide aparticulate dispensing apparatus that obviates or mitigates the abovedisadvantages.

DISCLOSURE OF THE INVENTION

According to one aspect of the present invention there is provided aparticulate dispensing apparatus for dispensing particulate refractorymaterial into a lining gap defined between an inner furnace surface andan expendable metal form, the particulate dispensing apparatuscomprising:

a platform supporting a carriage adjacent an upper end of the expendablemetal form, the carriage being pivotally coupled to the platform androtatable about a pivot point located generally at the center of theplatform;

a hopper coupled to the carriage, the hopper for receiving particulaterefractory material via an inlet and dispensing the particulaterefractory material through an outlet;

a feeder coupled to the outlet of the hopper, the feeder for moving theparticulate refractory material from the outlet to a dispenser, thedispenser being coupled to the carriage at a distal end of the feederand being suspended above the lining gap to deliver particulaterefractory material into the lining gap;

an air extractor device coupled to the carriage for removing air fromparticulate refractory material deposited in the lining gap and forre-compacting the particulate refractory material; and

driving means for rotating the carriage relative to the platform.

In the preferred embodiment, the feeder includes a trough coupled to thehopper outlet and an auger extending through the trough. The auger isrotatable to deliver particulate refractory material received from thehopper to the dispenser. Preferably, the auger includes a continuousblade having a pitch that increases in a direction toward the dispenser.

Preferably, the air extractor device includes a pair of reciprocatingforks and the dispenser includes a telescoping shaft. A sensor iscoupled to the dispenser fort detecting the level of particulaterefractory material in the lining gap. A controller is responsive to thesensor to adjust the length of the telescoping shaft.

An accumulator may be dispensed between the feeder and dispenser tostall the flow of particulate refractory material so that the dispenserreceives particulate refractory material at a constant rate. The hopperand feeder are configured to provide for smooth and consistent flow ofparticulate refractory material from the hopper to the accumulator.

According to another aspect of the present invention there is provided aparticulate dispensing apparatus for dispensing particulate refractorymaterial into a lining gap between an inner furnace wall and anexpendable metal form, the particulate dispensing apparatus comprising:

a platform supporting a carriage adjacent an upper end of the expendablemetal form, the carriage being pivotally coupled to the platform androtatable about a pivot point located generally at the centre of theplatform;

driving means for rotating the carriage relative to the platform;

a hopper coupled to the carriage, the hopper for receiving particulaterefractory material via an inlet and dispensing the particulaterefractory material through an outlet; and

a feeder coupled to the outlet of the hopper, the feeder having an augerextending through the length thereof having an encircling blade formoving the particulate refractory material from the outlet to adispenser, the dispenser being coupled to the carriage at a distal endof the feeder and being suspended above the lining gap to deliverparticulate refractory material into the lining gap;

wherein the auger blade has a variable pitch that increases in adirection toward the dispenser.

According to yet another aspect of the present invention there isprovided a particulate dispensing apparatus for dispensing particulaterefractory material into a gap between a furnace wall and a formcomprising:

a frame assembly disposed above the form and including a carriagemovable along a circular path above the gap;

a particulate refractory material feed assembly on the frame assemblyfor delivering particulate refractory material in a smooth andconsistent manner to a dispenser on the carriage, the dispenser beingsuspended above the gap and delivering particulate refractory materialinto the gap in a manner to reduce the occurrence of airborneparticulate material; and

a drive for moving the carriage.

The present invention provides advantages in that the foundry furnacecan be lined automatically while reducing the volume of airborneparticulate material that arises during the lining process. As a result,improved health conditions are provided for workers. The presentinvention also provides advantages in that since the air extractordevice removes air trapped in the particulate refractory material, thequality of the lining is improved. Furthermore, the present inventionprovides advantages in that the hopper and feeder design provide forsmooth and consistent flow of particulate refractory material to theretractable shaft assembly. This allows the particulate dispensingapparatus to be used with virtually any particulate refractory materialgrain size while still depositing a consistent lining.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described more fullywith reference to the accompanying drawings in which:

FIG. 1 is a front isometric view of a particulate dispensing apparatusin accordance with the present invention;

FIG. 2 is a rear isometric view of the particulate dispensing apparatusof FIG. 1;

FIG. 3 is an exploded front isometric view of a hopper, a feeder and anoperator platform of the particulate dispensing apparatus of FIG. 1;

FIG. 4 a is a front isometric view of portions of FIG. 1;

FIG. 4 b is a rear isometric view of FIG. 4 a;

FIG. 4 c is a top view of FIG. 4 a;

FIG. 4 d is a rear view of FIG. 4 a;

FIG. 4 e is a side view of FIG. 4 a;

FIG. 5 is an isometric view of portions of FIG. 3;

FIG. 6 is a side view of FIG. 5;

FIG. 7 a is a front isometric view of portions of FIG. 1;

FIG. 7 b is a rear isometric view of FIG. 7 a;

FIG. 8 is a front isometric view of portions of FIG. 1;

FIG. 9 is a front isometric view of portions of FIG. 1;

FIG. 10 is a rear isometric view of portions of FIG. 2;

FIG. 11 is an exploded isometric view of portions of FIG. 10; and

FIG. 12 is an exploded view of a lid lifter mechanism for a hopper.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIGS. 1 and 2, a particulate dispensing apparatus fordelivering particulate refractory material into the annular spacebetween an expendable form and an inner furnace surface is generallyshown at 10. The apparatus 10 includes a carriage 14 that is pivotallymounted to a circular platform 12 defining a rim 16. The rim 16 is sizedto fit about the open top of an expendable cylindrical form (not shown)installed within a foundry furnace (not shown). A base assembly 17 isdisposed beneath and supports the platform 12.

The carriage 14 is coupled to the platform 12 by a pivot assembly (notshown). The pivot assembly supports the carriage 14 and allows it torotate about a central vertical axis extending generally at a rightangle to the plane of the platform 12. A housing 18 is welded to thecarriage 14. A drive (not shown) contained within the housing 18 isactuable to rotate the carriage 14 relative to the platform 12.

A hopper 20 receives particulate refractory material, such as silica forexample, through an inlet and delivers the refractory material to anoutlet 36. The hopper 20 is supported above the housing 18 by a pair ofU-shaped side frames 22 that are welded to and extend outwardly from atop surface 24 of a hopper mounting plate 25. The hopper mounting plate25 is secured to the top of the housing 18 by bolts 23. The hopper 20includes a lid 26 that is pivotally coupled to a hopper body 28 toselectively cover the inlet of the hopper 20. A lid lifter assembly 30,which extends between the hopper body 28 and the lid 26, is actuable byan operator to raise and lower the lid 26. Electrical slip rings 32 areprovided on the lid 26 and are coupled to a power supply. In thismanner, the electrical slip rings 32 provide power to the particulatedispensing apparatus 10.

A feeder 34 is coupled to the outlet 36 of the hopper 20. The feeder 34receives the particulate refractory material and delivers it to adischarge chute 38 that is coupled to a feeder outlet 40 (shown in FIG.3). The discharge chute 38 in turn is coupled to an accumulator box 42.A dispenser, or retractable shaft assembly 44 is coupled to theaccumulator box 42 and receives particulate refractory material from thedischarge chute 38.

The particulate dispensing apparatus 10 further includes an operatorplatform 400 coupled to one side thereof. An operator typically mountsthe operator platform 400 via steps 406 in order to access the hopper20. The operator may use the operator platform 400 to direct bulk bagsof particulate refractory material into the hopper 20 when the hopper 20is being filled, for example. The operator platform 400 includesoutwardly extending struts 402 that are secured to brackets 404. Thebrackets 404 are mounted on an upper surface 24 of the hopper mountingplate 25.

A lifting assembly 410 having a hook 412 fastened thereto is provided toallow the entire particulate dispensing apparatus 10 to be lifted into afoundry furnace and removed from the foundry furnace followingcompletion of the lining production process. The lifting assembly 410includes a pair of arms 414 that are pivotally coupled to the hopperbody 28 by fasteners 416. A pair of channels 420 is welded to thecarriage 14 for receiving forks of a towing device (not shown). The pairof channels 420 provides an alternate means for transporting theparticulate dispensing apparatus 10.

Turning to FIGS. 3 and 4 a to 4 e, the hopper 20 and feeder 34 arebetter illustrated. As can be seen, hopper body 28 includes front andrear walls 21 and 23, respectively and opposing sidewalls 27 and 29. Thefront and rear walls 21 and 23 preferably extend upwardly and outwardlyfrom the hopper outlet 36 at an angle of approximately 30 degrees from avertical axis. The opposing sidewalls 27 and 29 also preferably extendupwardly and outwardly from the hopper outlet 36 at an angle ofapproximately 30 degrees from a vertical axis. The walls of the hopper20 are relatively steep to ensure that particulate refractory materialflows smoothly toward the hopper outlet 36.

The feeder 34 comprises an auger 50, which is coupled through a gearreducer 52 to a motor 54. The gear reducer 52 is secured the rear wall23 of the hopper body 28 by a mounting plate 60. A trough 56 surroundsthe auger 50 and is coupled to the gear reducer 52 through a rear endplate 58 by fasteners (not shown). The trough 56 is in communicationwith the outlet 36 of the hopper 20 and receives particulate refractorymaterial therefrom. The trough 56 is further supported by a spacer 62,which is located between the upper surface 24 of the hopper mountingplate 25 and the trough 56. The feeder outlet 40 is located forward ofthe front wall 21 and is generally aligned with the gap provided betweenthe inner surface of the furnace and the expendable form.

The auger 50 is rotatable about an auger axis 64 to move particulaterefractory material from a driven end 66 to an outlet end 68 of theauger 50. The blade 70 of the auger 50 has a variable pitch, whichincreases in length toward the outlet end 68 of the auger, as shown inFIGS. 5 and 6. The driven end 66 of the auger 50 includes a slot 72 forreceiving a key 74. The driven end 66 extends through the rear end plate58 of the trough 56 and through a plate 78 to engage the gear reducer52. A first bearing 76 is provided between the gear reducer 52 and theplate 78 to support the driven end 66 of the auger 50. The key 74 allowsrotational motion to be transferred from the gear reducer 52 to theauger 50. The outlet end 68 of the auger 50 extends through a trough endflange 80, a forward end plate 82, a second plate 84 and is supported bya second bearing 86.

A shroud 88 is provided in the trough 56 to maintain the particulaterefractory material in contact with the blade 70 of the auger 50. Theshroud 88 is formed of steel and is bolted to trough 56. A clearance ofapproximately ⅜ inches is provided between the auger 50 and the trough56 to inhibit jamming of the auger 50.

A trough cover 90 having an aperture 98 formed therein is provided tocover the forward end of the trough 56. The trough cover 90 is securedto the forward end of the trough 56 by fasteners (not shown). Holes 92are provided in the trough cover 90 and mating holes 94 are provided inan upper flange 96 of the trough 56. The holes 92 and 94 are aligned toreceive the fasteners. A lens 100 is secured to the trough cover 90 atthe location of the aperture 98 by a lens keeper 102. Lens keeper 102 iscoupled to the trough cover 90 by fasteners 104. The lens 100 allows anoperator to see inside the feeder 34 at the outlet end 68 of the auger50 and observe the flow of particulate refractory material. In apreferred embodiment, the aperture 98, lens 100 and lens keeper 102 forman illuminated inspection window.

Referring to FIGS. 7 a and 7 b, the discharge chute 38 is betterillustrated. As can be seen, discharge chute 38 includes a chute flange120 that extends from a lower edge of a chute body 122. The chute body122 is welded to the feeder outlet 40 of the trough 56 to directparticulate refractory material from the feeder 34 into the accumulatorbox 42.

Turning now to FIG. 8, the accumulator box 42 is shown. The accumulatorbox 42 receives particulate refractory material via the discharge chute38 at a rate that is determined by the rotational speed of the auger 50.The accumulator box 42 includes an inlet 110 that is surrounded by anupper flange 114, and a sloping wall 112 for directing particulaterefractory material towards an outlet 113. The outlet 113 has a smallercross-sectional area than the inlet 110 so that particulate refractorymaterial typically experiences a delay from the time it enters the inlet110 to the time it exits the outlet 113. Fasteners (not shown) areprovided to secure the upper flange 114 of the accumulator box 42 to thechute flange 120 of the discharge chute 38. A lower flange 116 surroundsthe outlet 113 of the accumulator box 42 and is provided for mating witha connecting flange 118 of the retractable shaft assembly 44.

The retractable shaft assembly 44 is shown in FIG. 9. A connecting plate120 is provided between the lower flange 116 of the accumulator box 42and the connecting flange 118 of the retractable shaft assembly 44. Theretractable shaft assembly 44 includes a main shaft 124, a firstretractable shaft 126 and a series of intermediate shafts 128. Fourintermediate shafts 128 are shown, however, any number of shafts 128 maybe used to achieve the desired length. The intermediate shafts 128 andthe first retractable shaft 126 telescope from the main shaft 124between a retracted position and an extended position. The main shaft124 and the intermediate shafts 128 each include an upper flange 130having a lug 132 projecting from a side edge thereof. A pair of tuberetainers 134 is provided adjacent opposing sides of the upper openings136 in each of the shafts 124 and 128 respectively. Cables (not shown)extend through holes 138 provided in the upper flange 130 and the tuberetainers 134 to enable the overall length of the retractable shaftassembly 44 to be adjusted.

A level sensor generally indicated at 155 is provided to detect theheight of the particulate refractory material deposited in the lininggap. The level sensor 155 is coupled to the retractable shaft assembly44 at a lower end of the main shaft 124. The level sensor 155 comprisesa limit trip blade 140 that is coupled to a limit switch trip arm 142.Fasteners 146 extend through a slot 148 provided in the limit trip blade140 and mate with holes 150 provided in the limit switch trip arm 142.The limit trip blade 140 includes a surface-contacting flange 160 thatcontacts the particulate refractory material deposited in the lining gapas the retractable shaft assembly 44 moves along the lining gap path.The limit switch trip arm 142 is coupled to a projecting lug 150 by abolt assembly 152 and a nut 154 and is pivotable about a pivot axis 144.An upper end 162 of the limit switch trip arm 142 selectivelycommunicates with a cable controller box 156 to adjust the cable lengthand thereby control the length of the retractable shaft assembly 44. Theretractable shaft assembly 44 retracts when the forward progress of thelimit trip blade 140 is resisted by particulate refractory material ofincreased depth within the lining gap. Resistance to the forwardmovement of the limit trip blade 140 causes the limit switch trip arm142 to move into contact with the cable controller box 156. This causesthe cable controller box 156 to shorten the cable length byapproximately ½ inch. As a result, the limit switch trip arm 142 movesout of contact with the cable controller box 156 and thesurface-contacting flange 160 again contacts the surface of theparticulate refractory material deposited in the lining gap.

Referring now to FIG. 10, an air extractor device 170 and an airextractor mount assembly 190 are generally shown. The air extractormount assembly 190 comprises an air extractor mounting plate 192. Theair extractor mounting plate 192 is secured to a side panel of thehousing 18 by fasteners 194. As shown in FIG. 11, a bracket assembly 202projects from the mounting plate 192. A tilt unit frame 196 is coupledto upper and lower bracket members 198, 200 of the bracket assembly 202.The tilt unit frame 196 is generally C-shaped and includes a centralbody 204 and a pair of free arms 206. Each free arm 206 generally hasU-shaped cross-section. A tilt unit 208 includes an upper lug 210 havinga slot 212 formed therein and a lower lug 214 having an aperture 216formed therein. The upper and lower lugs 210, 214 are sandwiched withinthe U-shape of the free arms 206 and are secured thereto. The slot 212of the upper lug 210 is aligned with an aperture 220 formed in the upperfree arm and receives an adjustable handle 218. The aperture 216 of thelower lug 214 is aligned with an aperture 222 of the lower free arm andreceives a pivot pin 224.

A turnbuckle assembly 226 is provided between the tilt unit frame 196and the tilt unit 208 for adjusting the distance therebetween andallowing the tilt unit 208 to pivot about the pivot pin 224. Theturnbuckle assembly 226 is linked to a hand wheel 228 through anadjusting screw 230 by a key 236. The adjusting screw 230 is coupled tothe hand wheel 228 through a bearing block 232, which is secured to adistal edge 234 of the tilt unit 208. A box ratchet 227 is provided toenable the turnbuckle assembly 226 to be manually adjusted.

An air extractor guard 238 surrounds the air extractor mount assembly190 to protect the assembly 190 against accidental impact, which couldcause the hand wheel 228 to move. Further, the air extractor guard 238is provided to protect the operator from the moving parts of the airextractor device 170.

The air extractor device 170 is coupled to the tilt unit 208 of the airextractor mount assembly 190 and comprises a pair of reciprocating forks172 coupled to a fork housing assembly 174. Each reciprocating fork 172includes a prong assembly 176 that is secured to a lower end thereof.The prong assembly 176 includes a frame 178 having a plurality ofdownwardly extending prongs 180 coupled thereto. The reciprocating forks172 are driven by an air extractor drive (not shown). The air extractordrive includes a cam that is coupled to the fork housing 174 to adjustthe overall fork 172 height as the level of the particulate refractorymaterial in the lining gap increases. The cam regularly lifts thereciprocating forks 172 above the surface of the particulate refractorymaterial and then drops them down to the surface of the particulaterefractory material. When dropped, the prongs 180 of the reciprocatingforks 172 extend fully into the particulate refractory material withinthe lining gap and the frame 178 generally rests on top of theparticulate refractory material. The up and down movement of the prongs180 causes the particulate refractory material deposited within thelining gap to be re-compacted. The air extractor mount assembly 190 aidsin the removal of air from the particulate refractory material byallowing the angle at which the air extractor device 170 contacts theparticulate refractory material to be adjusted.

Referring to FIG. 12, the lid lifter mechanism 30 is shown. The lidlifter mechanism 30 includes a support 430 that extends from the rearwall 23 of the hopper 20. A threaded lifting assembly 432 is coupled tothe support 430 by mounting plates 440 and 442 that are secured byfasteners 444 and 446, respectively. The threaded lifting assembly 432includes a tube 436 that receives a threaded member 438. First andsecond washer elements 450 and 452 are provided between the threadedmember 438 and the mounting plate 442. The threaded member 438 iscoupled to a hand wheel 448 so that rotation of the hand wheel 448causes the threaded member 438 to move axially. A post 454 extends fromthe lid 26. The post 454 is mounted in the tube 436 and abuts thethreaded member 438. Thus, rotation of the hand wheel 448 causes the lidto be raised or lowered. As shown in FIG. 2, a lid rotating arm 31 isprovided for rotating the lid 26 out of the way of the inlet of thehopper 20. The lid rotating arm 31 is actuable once the lid 26 has beenraised by the lid lifter mechanism 30. The lid rotating arm 31 pivotsthe lid 26 approximately 180 degrees away from the inlet of the hopper20 to allow the hopper 20 to be filled with particulate refractorymaterial.

During foundry furnace lining, the furnace bottom is compacted using avibrating plate, and thereafter, the expendable form is centrallyinstalled in the foundry furnace. The particulate dispensing apparatus10 is then placed on the top of the expendable form in order to positionthe retractable shaft assembly 44 above the lining gap. Once theparticulate dispensing apparatus 10 is in position, the lid 26 is raisedand pivoted to uncover the inlet and the hopper 20 is filled withparticulate refractory material. The particulate refractory materialpoured in the hopper 20 falls through the hopper 20, past the hopperoutlet 36 and into the trough 56 of the feeder 34.

The driving means of the carriage 14 is then initiated to rotate theparticulate dispensing apparatus 10 about the pivot axis of the platform12 at a predetermined velocity. The feeder 34 is started by switching onthe motor 54 and the air extractor is started by switching on the airextractor drive.

The auger 50, of the feeder 34, rotates about its axis to move theparticulate refractory material through the trough 56 from the outlet 36of the hopper 20 to the outlet 40 of the feeder 34. The spacing of theauger blade 70 controls the rate at which the particulate refractorymaterial is moved towards the feeder outlet 40. The particulaterefractory material then falls from the feeder outlet 34, through thedischarge chute 38, and into the accumulator box 42. The reducedcross-sectional area of the outlet of the accumulator box 42 stalls theparticulate refractory material so that it enters the retractable shaftassembly 44 at a predetermined flow rate.

The retractable shaft assembly 44 rotates with the carriage 14 todispense particulate refractory material into the lining gap. Theparticulate dispensing apparatus 10 preferably delivers approximately 2inches of particulate refractory material per revolution. As the depthof the particulate refractory material in the lining gap increases, theretractable shaft assembly 44 retracts to maintain thesurface-contacting flange 160 in light contact with the surface of theparticulate refractory material.

The air extractor device 170 also rotates with the carriage 14. Thereciprocating forks 172 of the air extractor device 170 re-compact theparticulate refractory material deposited in the lining gap to removeair therefrom. The air extractor device 170 moves upward as the depth ofthe particulate refractory material increases so that the prongs 180 ofthe reciprocating forks 172 continually contact the top portion of theparticulate refractory material. The operator can use the hand wheel 228to adjust the angle at which the reciprocating forks 172 contact theparticulate refractory material to optimize the air extraction process.Removal of the air from the particulate refractory material ensures thata high quality lining is produced.

Particulate refractory material continues to be dispensed into thelining gap and re-compacted by the air extractor device 170 until thedesired lining height has been reached. Once the desired lining heightis reached, the particulate dispensing apparatus is removed from theexpendable form. The lining is vibrated and then sintered, with theexpendable form in place, to produce a continuous furnace lining.

Dispensing the particulate refractory material using the retractableshaft assembly 44 has an advantage in that the amount of airborne dustthat arises as the particulate refractory material is dispensed isreduced because the particulate refractory material falls only a shortdistance before coming to rest. It is particularly important to reducethe amount of airborne particles when the particulate refractorymaterial being dispensed is silica. The retractable shaft assembly 44reduces the volume of airborne silica particles that may be inhaled byworkers during the preparation of a foundry furnace lining.

The particulate dispensing apparatus 10 has applications in steel,ferrous and non-ferrous foundries. Applications include: lining ofvertical channel furnaces, mechanical iron pouring ladles and transferladles.

Although a preferred embodiment of the present invention has beendescribed, those of skill in the art will appreciate that variations andmodifications may be made without departing from the spirit and scopethereof as defined by the appended claims.

1. A particulate dispensing apparatus for dispensing particulaterefractory material gap between a furnace wall and a form comprising: aframe assembly disposed above said form and including a carriagemoveable along a circular path above said gap; a particulate refractorymaterial feed assembly on said frame assembly for delivering particulaterefractory material in a smooth and consistent manner to a dispenser onsaid carriage, said dispenser delivering particulate refractory materialinto said gap and being suspended above and extendable into said gap toreduce the distance the particulate refractory material falls thereby toreduce the occurrence of airborne particulate material; and a drive formoving said carriage.
 2. A particulate dispensing apparatus as claimedin claim 1 wherein said feed assembly comprises a hopper and a feeder,said hopper and feeder being configured to provide said smooth andconsistent flow of particulate refractory material to said dispenser. 3.A particulate dispensing apparatus as claimed in claim 2 wherein saidhopper has an outlet and includes generally steep inclined walls toprovide smooth flow of particulate refractory material to the outlet. 4.A particulate dispensing apparatus as claimed in claim 3, wherein saidfeeder comprises a trough coupled to the outlet of said hopper forreceiving said particulate refractory material and an auger coupled tosaid carriage and extending through said trough, said auger rotatingabout an auger axis to move particulate refractory material from theoutlet of said hopper to said dispenser.
 5. A particulate dispensingapparatus as claimed in claim 4, wherein said auger includes acontinuous blade, the pitch of said blade increasing in a directiontowards said dispenser.
 6. A particulate dispensing apparatus as claimedin claim 5 further comprising an accumulator disposed between saidfeeder outlet and said dispenser, said accumulator delaying the progressof particulate refractory material from said feeder to said dispenser.7. A particulate dispensing apparatus as claimed in claim 1 furthercomprising an air extractor device coupled to said carriage for removingair from particulate refractory material deposited in said gap and forrecompacting the deposited particulate refractory material.
 8. Aparticulate dispensing apparatus as claimed in claim 7, wherein said airextractor device comprises a pair of reciprocating forks.
 9. Aparticulate dispensing apparatus as claimed in claim 8, wherein saiddispenser comprises a telescoping shaft for receiving particulaterefractory material from said feeder and delivering the particulaterefractory material to said gap.
 10. A particulate dispensing apparatusas claimed in claim 9, further comprising a sensor coupled to saiddispenser for detecting the level of the particulate refractory materiallocated in said gap and a controller for adjusting the length of saidtelescoping shaft to maintain said dispenser above the particulaterefractory material located in said gap.
 11. A particulate dispensingapparatus as claimed in claim 10 further comprising a viewing windowadjacent to said feeder.
 12. A particulate dispensing apparatus fordispensing particulate refractory material into a lining gap definedbetween an inner furnace surface and an expendable metal form, saidparticulate dispensing apparatus comprising: a platform supporting acarriage adjacent an upper end of said expendable metal form, saidcarriage being pivotally coupled to said platform and rotatable about apivot point located generally at the center of said platform; a hoppercoupled to said carriage, said hopper for receiving particulaterefractory material via an inlet and dispensing said particulaterefractory material through an outlet; a feeder coupled to the outlet ofsaid hopper, said feeder for moving the particulate refractory materialfrom said outlet to a dispenser, said dispenser being coupled to saidcarriage at a distal end of said feeder and being suspended above andextendable into said lining gap to reduce the distance the particulaterefractory material falls thereby to reduce the occurrence of airborneparticulate material; an air extractor device coupled to said carriagefor removing air from particulate refractory material deposited in saidlining gap and for re-compacting the particulate refractory material;and a drive for rotating said carriage relative to said platform.
 13. Aparticulate dispensing apparatus as claimed in claim 12, wherein saidfeeder comprises a trough coupled to the outlet of said hopper forreceiving said particulate refractory material and an auger coupled tosaid carriage and extending through said trough, said auger rotatingabout an auger axis to move particulate refractory material from theoutlet of said hopper to said dispenser.
 14. A particulate dispensingapparatus as claimed in claim 13, wherein said auger includes acontinuous blade, the pitch of said blade increasing in a directiontowards said dispenser.
 15. A particulate dispensing apparatus asclaimed in claim 12, wherein said air extractor device comprises a pairof reciprocating forks.
 16. A particulate dispensing apparatus asclaimed in claim 12, wherein said dispenser comprises a telescopingshaft for receiving particulate refractory material from said feeder anddelivering the particulate refractory material to said lining gap.
 17. Aparticulate dispensing apparatus as claimed in claim 16, furthercomprising a sensor coupled to said dispenser for detecting the level ofthe particulate refractory material located in said lining gap and acontroller for adjusting the length of said telescoping shaft tomaintain said dispenser above the particulate refractory materiallocated in said lining gap.
 18. A particulate dispensing apparatus asclaimed in claim 17, wherein said feeder comprises a trough coupled tothe outlet of said hopper for receiving said particulate refractorymaterial and an auger coupled to said carriage and extending throughsaid trough, said auger rotating about an auger axis to move particulaterefractory material from the outlet of said hopper to said dispenser.19. A particulate dispensing apparatus as claimed in claim 18, whereinsaid auger includes a continuous blade, the pitch of said bladeincreasing in a direction towards said dispenser.
 20. A particulatedispensing apparatus as claimed in claim 19, wherein said air extractordevice comprises a pair of reciprocating forks.
 21. A particulatedispensing apparatus as claimed in claim 12, further comprising anaccumulator coupled between said feeder outlet and said dispenser, saidaccumulator for delaying the progress of particulate refractory materialfrom said feeder to said dispenser.
 22. A particulate dispensingapparatus as claimed in claim 12, wherein said hopper and feeder areconfigured to provide smooth and consistent flow of particulaterefractory material to said dispenser.
 23. A particulate dispensingapparatus as claimed in claim 22 wherein said hopper includes generallysteep inclined walls to provide smooth flow of particulate refractorymaterial to the outlet thereof.
 24. A particulate dispensing apparatusas claimed in claim 23, wherein said feeder comprises a trough coupledto the outlet of said hopper for receiving said particulate refractorymaterial and an auger coupled to said carriage and extending throughsaid trough, said auger rotating about an auger axis to move particulaterefractory material from the outlet of said hopper to said dispenser.25. A particulate dispensing apparatus as claimed in claim 24, whereinsaid auger includes a continuous blade, the pitch of said bladeincreasing in a direction towards said dispenser.
 26. A particulatedispensing apparatus as claimed in claim 25 further comprising anaccumulator disposed between said feeder outlet and said dispenser, saidaccumulator delaying the progress of particulate refractory materialfrom said feeder to said dispenser.
 27. A particulate dispensingapparatus as claimed in claim 12 further comprising a viewing windowadjacent said feeder.
 28. A particulate dispensing apparatus fordispensing particulate refractory material into a lining gap between aninner furnace wall and an expendable metal form, said particulatedispensing apparatus comprising: a platform supporting a carriageadjacent an upper end of said expendable metal form, said carriage beingpivotally coupled to said platform and rotatable about a pivot pointlocated generally at the centre of said platform; driving means forrotating said carriage relative to said platform; a hopper coupled tosaid carriage, said hopper for receiving particulate refractory materialvia an inlet and dispensing said particulate refractory material throughan outlet; and a feeder coupled to the outlet of said hopper, saidfeeder having an auger extending through the length thereof having anencircling blade for moving the particulate refractory material fromsaid outlet to a dispenser, said dispenser being coupled to saidcarriage at a distal end of said feeder and being suspended above andextendable into said lining gap to reduce the distance the particulaterefractory material falls thereby to reduce the occurrence of airborneparticulate material; wherein said auger blade has a variable pitch thatincreases in a direction toward said dispenser.
 29. A particulatedispensing apparatus as claimed in claim 28, wherein said dispensercomprises a telescoping shaft for receiving particulate refractorymaterial from said feeder and delivering the particulate refractorymaterial to said lining gap.
 30. A particulate dispensing apparatus asclaimed in claim 29, further comprising a sensor coupled to saiddispenser for detecting the level of the particulate refractory materiallocated in said lining gap and a controller for adjusting the length ofsaid telescoping shaft to maintain said dispenser above the particulaterefractory material located in said lining gap.
 31. A particulatedispensing apparatus as claimed in claim 28, wherein said hopper andfeeder are configured to provide smooth and consistent flow ofparticulate refractory material to said dispenser.
 32. A particulatedispensing apparatus as claimed in claim 31 wherein said hopper includesgenerally steep inclined walls to provide smooth flow of particulaterefractory material to the outlet thereof.
 33. A particulate dispensingapparatus as claimed in claim 32 further comprising an accumulatordisposed between said feeder outlet and said dispenser, said accumulatordelaying the progress of particulate refractory material from saidfeeder to said dispenser.